| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for differential exhaust which enables the extraction of a particle beam in an atmospheric pressure, makes it possible to extract the particle beam with a longer working distance kept in the atmospheric pressure and enables the extraction of a large-diameter particle beam. SOLUTION: This device is equipped with a vacuum chamber 2, an atmosphere chamber 3 where the pressure is maintained at the atmospheric pressure or lower or higher, a bulkhead 4 that separates the vacuum chamber 2 and the atmosphere chamber 3, a rotor 7 that is located in the bulkhead 4 and can rotate and passages 8 and 11 that are formed in the bulkhead 4 and connects the vacuum chamber 2 and the atmosphere chamber 3. Holes 72 are made in the rotor 7, and the vacuum chamber 2 communicates with the atmosphere chamber 3 when one of the holes 72 of the rotor 7 fits the communicating passages 8 and 11. The pressures in the vacuum chamber 2 and the atmosphere chamber 3 can be maintained stably and the communication between both chambers can be secured through the rotation of the rotor 7.
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